Treating of animal-skin products



85 tainin Patented Oct. 7, 1930 "UNITED STATES y imemssam or mam, ,rratr, assmxon TO socm'rA nwanz om nnnvm'rr anonnui ronmo, or'runm, ITALY mnmrmeor Airman-511m rnonuc'rs No Drawing. Application many 24, 1929, Serial no. cause, and in Italy 1111714, 1928. I

This invention relates to a process of treat} ing animal skin materials or animal skin products as distinguished from the ;,treatmentof wool, hair, etc., and has for one of its objects the provision of a process adapted for utilizing untanned hides and scraps and cuttings therefrom, as well aslscraps and cuttingsfrom tanned hides, whereby such materials may beconverted into a; useful and valuable product which in appearance,

fibrous texture and flexibility resembles natural leather. I

of great economical value in that it salvages or utilizes materials which heretofore have I generally been converted into gluesorfertilizers orsimply thrown away v e i In the practice of my invention when treating untanned animal skin material or-animal skin products, scraps and cuttlngstherefrom the fibers of the material are intimately and mechanically admixed with an a ueous medium until a thin flowing slurry oi the fibers in aqueous suspension isobtained. }The pro- '25 portion of the aqueous medium tothe material being treated-is necessarily large'so 'promotlngthe abstracting of the liquid of as to obtain the desired thin mass or slurry which willreadily flow, and which ,for purposes ofdescription shall be referredto as a0 afiowing or fiowableslurry. I

I next add tovthe slurry a tanning agent which maybe a natural or a synthetic vegetable or mineral tannin agent, a fiber lubricant, and a suitable blnding material con-.

a water insoluble binder, forflexample in ia rubber latex, gutta percha latex, ba-lata latex or the like, as obtained from the trees and which may havexbeen preserved by ammonia or any other suitable alkaline preserving material. A synthetic latex, or other binding material containing a water insoluble binder and which is in suitablecondition for incorporation in the slurry may I be substituted fortheflatices above mentioned. o i

A suitable substance-is employed for preserving the binding material in the product.

When latex is used as a'binding material I avoid the vulcanizing treatment otherwise required for preserving said latex by using vegetable tannin, which is employed as a tannmg agent in the tanning treatment monk employ those of the pyrogallicseries, more particularly sumach. mineral tanning agents I can employ particnlarlythosecontaining chromium.

A suitable fiber lubricant, i. e.

added to the slurry either before, during. or after the addition of the tanning agent and always before adding the binding material.

Upon the addition of the binding material e to the slurry the binder thereof is precipitated upon the fibers being treated.

Inasmuch as the liquid of theslurry must v be abstracted in the urther practice of my process I may add to, the slurry; a material an oilor grease e'mulsifiable in water such, as chroi I .mine (a sulphurated oil), or example, is It will be apparent that my invention is such as commercial sodium chloride, which contains magnesium and calcium chlorides and other impurities, or a suitable equivalent. of sodium chloride, such as ammonium chloride, or the like, the addition of this materialthe slurry and being of material advanta e in the making of sheets of substantial thic ness. I have found also that'sodiumchloride or an equivalent thereofadded directlyafter the latex andbefore abstracting the liquid I tions employed in the finishing of natural leathers. I 1 I 1 y I In the treatment of tanned animal skin products, as distinguished fromnntanned products such as those above referred to when I employ cuttings of chrome tanne leather from which the acid has vnot yet been removed, the material isfirst subjected to a preliminary .neutralization by treatment with an alkaline salt of a. weak acid, such as neutrol bicarbonate of soda and sodium sulphate) borate of sodium, sodium hyposulphite, bicarbonate of soda, either sepaservative of the binder in the product, so that vulcanization is dispensed with. In the treatment of vegetable tanned animal skin products, I prefer to add a mineral tanning agent, such as chrome, followed by a neutralization. I may next carry out a light vegetable tannage, preferably with sumach, for preserving the latex, but this is not strictly necessary. the animal skin products being treated already containing vegetable tannin which will act as a preservative of the binder.

In the treatment of mineral tanned animal skin roducts, if desired, and especially when a finished material of improved tensile and breaking strength is the desideratum, I add a detanning agent, such as an organic detanning salt, either to the aqueous suspension or during the admixing of the fibers with an aqueous medium and preferably after the neutralization above described. Examples of an organic detanning salt suitable for my purpose are Seignettes salt (sodium potassium tartrate), cream of tartar (acid potassium tartrate) and other organic detanning salts. From my own experience I prefer Seignettes salt.

A natural vegetable tanning agent such as sumach or a synthetic tanning agent having equivalent properties and a binding material containing a natural or s nthetic latex binder in suitable condition or addition to the slurry are then added to the slurry. A grease or oil capable of emulsifying when added to water is also added to the slurry either before, during or after the addition of the tanning agent.

If detanning has previously been resorted to as above described then the amount of vegetable tannin employed as tanning and latex reserving agent should not be suificient to destroy the effect of the detanning. In order to permit a uniform absorption of this reduced amount of vegetable tannin through all the fibrous particles in the aqueous suspension, I previously add the fiber lubricant. In order to prevent shrinkage of the previously detanned fibers during greasing. more especially when chromine is used, I add to the oil or grease a certain amount of soap.

The binding material used, as above noted, must comprise a water insoluble binder and as examples of a suitable binding material I may mention rubber latex, gutta percha latex, balata latex or the like as obtained from the trees and which may be preserved by ammonia or other suitable alkaline preserving material. A synthetic latex, or other binding material containing a water insoluble binder which is in suitable condition for incor oration in the slurry, however, may be use satisfactorily.

The latex is added to the aqueous slurry after the addition of the oil or grease and after the supplementary tanninq treatment.

The grease or oil above mentioned, these terms having been used synonymously, is one capable of emulsifying when added to water, of which chromine is an example, this material being added at a temperature between 30 and 60 C.

In some instances I add alum and a tanning agent such as chrome liquor to the aqueous slurry and neutralize before the addition of the binder.

In the treatment of tanned fibers as above mentioned in connection with the treatment of untanned fibers I may add commercial sodium chloride, or its equivalent, such as ammonium chloride or the like, to the aqueous suspension of the fibres in order to promote the abstracting of the liquid of the slurry, when sheets of substantial thickness are desired in the finished product.

It is to be understood that the amount of sodium chloride will vary depending upon the material being treated and also depending upon the separation or abstracting of the. liquid of the slurry that is desired in the felting of the product into sheets.

I have ascertained also that the addition of sodium chloride or its equivalent directly after the addition of latex and before the liquid of the slurry is abstracted highly improves the process and the product.

I find in. the practice of my invent-ion both with respect to the treatment of untanned as well as tanned materials some care must be exercised so as not to allow coagulation of the binder employed to proceed to a detrimental degree before the liquid of the slurry is abstracted. inasmuch as such detrimental coagulation renders the felting and the properties of the product unsatisfactory. In employing latex as a binding material I prefer to abstract the liquid of the slurry, i. e., felt, Within an hour of the addition of the binding material to the slurry.

In some cases, particularly when a soft finished product is desired, I add pure or impure glucose or a mixture of glucose and dextrine, or potato starch or other leather nourishing substances, to the slurry, or to the tan ning agent, or to the grease.

In all cases some choice is left to the operator as to the various proportions of materials used and a great deal depends upon the use to Chrome tanned leather 69 Neutrol bicarbonate of soda and sodium sulphate) 9.800 Chromine (a sulphurated oil) 18.400 Sumach extract 69 40% latex Sodium chloride 30' In the manufacture of materials suitable 'Kilograms Chrome tanned leather Neutrol 8.500 Seignettes salt 2 Chromine 12 kg., soap 6 kg., glycerine 3 kg 21 Sumach extract 1O 40% latex 30 Sodium chloride 30 When it is desired to employ the finished product as sole leather or for other purposes requiring a considerable stiflness in the product the addition of grease may be omitted.

Dyeing is effected preferably by the addition of a dye to the slurry, and acid aniline dyes are preferred.

The invention above described in which specific mention is made of the treatment of mineral tanned products wherein thematerial is first neutralized, then washed, after which it is mixed with water to form a slurry to which grease, a binder and a preservative for the binder and if desired sodium chloride are added, has been made the basis of my copending divisional application Serial No. 468,122, filed July 15, 1930.

The invention above described in which mineral tanned animal skin products are first neutralized, washed, reduced to a flowing aqueous slurry and then treated with a detanning agent, after which grease, a binder and a preservative for the binder, and if desired sodium chloride are added to the slurr constitutes the subject matter of-my copen ing divisional application Serial No. 468,123, filed July 15, 1930.

The invention above described 'in which a taming agent, a material such as ammonium chloride and a water insoluble binder are added to an aqueous slurry of untanned animal skin products constitutes the subject matter of my copending divisional application Serial No. 468,124, filed July 15, 1930.

The invention herein described in which a grease, ammonium chloride, a water intannin subject matter of my copendin animal skin fibers constitutes the subject matter of my copendin divisional application Serial N 0. 468,125, ed July 15, 1930.

The invention herein described in which a tanning agent, a grease, a water insoluble 7 binder and if desired a material such as sodium chloride are added to an a ueous slurry of tanned fibers has been ma e the subject matter of my copendin divisional application Serial No. 468,126,fi ed July 15,

The invention above described in which 9. agent, material such as ammonium chlori e, etc. are added to an aqueous slurry of tanned animal skin fibers constitutes the divisional ed J uly 15,

application Serial No. 468,127, 1930.

The invention above described in which dextrine is added to an aqueous slurry of animal skin products has been made the subject matter of In copending divisional applies-tion Serial 10. 468,128, filed July 15, 1930.

The invention above described in which potato starch is added to an aqueous slurry of animal skin products has been made the subject matter of my copendin divisional application SerialNo. 468,129, fi ed July 15, 1930.

What I claim is i u '1. The process which'comprises adding a mineral tanning agent and. a grease to a flowing aqueous slurry containing the fibrous portions of animal skin products in suspension, adding a water insoluble binder and a preservative therefor to the slurry, and abstracting the liquid of the slurry.

2. The'process which comprises mechanically and intimately admixing untanned animal skin products and an aqueous medium until a thin flowing slurry containing the, fibrous portions of the animal skin products being treated in suspension is obtained, adding a mineral tanning agent, a neutralizing agent and a grease and thereupon adding vegetable tannin and latex to the slurry thus obtained, and abstracting the liquid of the slurry.

3. The process which comprises mechan- Ill -ically and intimately admixing untanned 4. The process which comprises adding a mineral tanning agent containing chromium, a neutralizing agent, and a grease to a flowing aqueous slurry containing the fibrous por' tions of untanned animal skin; products in suspension, adding a vegetable tannin and rubber latex to the slurry, and abstracting the liquid of the slurry.

5. The process which comprises addin a vegetable tanning agent of the pyroga lic series and a grease to a flowing aqueous slurry containing the fibrous portions of untanned animal skin products in suspension, adding latex to the slurry, and abstracting the liquid of the slurry.

6. The process which comprises adding a mineral tanning agent and a grease to a flowing aqueous slurry containing the fibrous portions of untanned animal skin products in suspension, adding sodium chloride and thereupon a water insoluble binder and a preservative therefor to the slurry, and abstracting the liquid of the slurry.

7. The process which comprises adding a mineral tanning agent and a grease to a flowing aqueous slurry containing the fibrous portions of untanned animal skin products in suspension, adding a water insoluble binder a preservative therefor and sodium chloride to the slurry, and abstracting the liquid of the slurry.

8. The process which comprises adding chrome liquor and alum to a flowing aqueous slurry containing the fibrous portions of animal skin products in suspension, adding a neutralizing agent, a fiber lubricant and latex, and abstracting the liquid of the slurry.

9. The process which comprises adding a tanning agent and chromine to a flowing aqueous slurry containing the fibrous portions of animal skin products in suspension, adding a water insoluble binder and a preservative therefor to the slurry, and abstracting the liquid of the slurry.

10. The process which comprises adding a tanning agent, a grease and glucose to a flowing aqueous slurry containing the fibrous portions of animal skin products in suspension, adding a water insoluble binder and a preservative therefor to the slurry, and abstracting the liquid of the slurry.

11. The process which comprises mechanically and intimately admixing animal skin products and an aqueous medium until a flowing slurry containing the fibrous portions of the animal sln'n products being treated in suspension is obtained, adding a tanning agent, a grease, a water insoluble binding material and a preservative therefor, the binder of the binding material precipitating and coagulating upon the fibers of the slurry, and abstracting the liquid from the slurry to obtain a sheet before coagulation has progressed to a detrimental degree.

12. The process of treating animal skin products which comprises adding a tanning agent, a grease and a latex to a flowing slurry containing the fibers of the skin products being treated in aqueous suspension, and ab- May, 1929.

ANTONIO FERRETTI. 

